children s illustrated encyclopedia ocean life...waters to hunt for prey. deep-living sharks and...

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Orpheus

C O N T E N T S

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CONTENTS

4 OCEANSOcean currents • The ocean floor • Ocean habitats

6 SURFACE WATERSPlankton • Sea birds • Rich variety of life

8 DEEPWATER LIFEBioluminescence

10 OCEAN FLOORScavengers and predators 4500 metres down

12 BLACK SMOKERSAmazing creatures of the mid-oceanic ridge

14 OCEAN TRENCHES

15 OCEAN EXPLORATIONSubmersibles, robots and scuba divers

16 OCEAN GIANTSBlue whale, sperm whale, giant squid, great white shark etc., to scale

18 SEASHORELife in tidal pools • What causes tides

20 CORAL REEFS

22 MANGROVES

24 ISLAND LIFEHow islands are colonized • Island giants

26 ARCTICLife above and below the ice

27 TUNDRAPlants and animals in the short Arctic summers

28 ANTARCTICAWhales, penguins and seals

30 ENDANGERED OCEANSOcean pollution • Fishing, hunting and habitat destruction

32 INDEX

First published in 2009 by Orpheus Books Ltd., 6 Church Green, Witney, Oxfordshire OX28 4AW England

www.orpheusbooks.com

Copyright © 2009 Orpheus Books Ltd

Created and produced by Orpheus Books Ltd

Text Claire Aston, Steve Parker

Consultant Steve Parker BSc Scientific Fellow of the Zoological Society

Illustrators Susanna Addario, Mike Atkinson, Andrew Beckett, John Butler,Martin Camm, Ferruccio Cucchiarini, Elisabetta Ferrero, Giuliano Fornari,Andrea Ricciardi di Gaudesi, Gary Hincks, Ian Jackson, David More, JohnMorris, Steve Noon, Nicki Palin, Alessandro Rabatti, Eric Robson, ClaudiaSaraceni, Peter David Scott, Ivan Stalio, Colin Woolf, David Wright

All rights reserved. No part of this book may be reproduced, stored in aretrieval system, or transmitted in any form or by any means, electronic,

mechanical, photocopying, recording or otherwise, without the prior writtenpermission of the copyright owner.

ISBN 978 1 905473 60 1

A CIP record for this book is available from the British Library.

Printed and bound in Singapore

C O N T E N T S

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T H E O C E A N F LO O RThe ocean floor is mostly a level plain, butit also features mountain ranges, volcanicpeaks, long ridges, deep trenches and highledges where it borders the continents.

ThePacificOcean, twiceas large as theAtlantic, covers athird of the Earth.

The flat plain that forms most of theocean is called the abyssal plain. It lies at anaverage depth of about 4500 metres and iscovered by a thick layer of sediment calledooze. This consists of mud and gravel—andbillions of skeletons of dead animals thathave collected at the bottom. Thecontinental shelf, the ledge that surroundsthe abyssal plain, plunges relatively steeplydown to it at the continental slope. Thewater above the continental shelf, really apart of the continent that lies under theocean, is never deeper than 200 metres. It ishere that most ocean life is found.

This (above) isa rectangular slice

of ocean showing itsundersea features. The mid-

oceanic ridge runs all the wayaround the Earth. The ridge is made by

magma (molten rock), rising up frombeneath the Earth’s crust. As the rock cools,

solidifies and spreads outwards, the ocean floorspreads wider. Meanwhile, other parts of the ocean floor

are gradually sinking down beneath the continents in deep-ocean trenches, the deepest places on Earth.

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Continental shelf

Continental rise

Continental slope

Abyssalplain

Abyssal plain

Seamounts

Sea level

Oceanic island

Mid-oceanic ridge

Trench

Magmarising

OCEANS

THE OCEANS cover more than 360million square kilometres of the Earth’s

surface, approximately 71% of its total area.More than 1350 million cubic kilometres ofwater is contained within it, representingnearly 97% of the Earth’s entire supply. Theoceans hold enough salt in them to coverEurope to a depth of five kilometres. Thereare four great oceans: in order of size, thePacific, Atlantic, Indian and Arctic Oceans(some would add a fifth, the SouthernOcean, surrounding Antarctica).

The ocean waters are not still, but movein tides and currents. Tides shift the waterdaily under the gravitational pull of theMoon (see page 19). Currents, great flowingbands of water, swirl around the globe.There are two kinds: surface currents, whichare swept along by the wind, and deepwatercurrents, which are generated by differencesin density (the colder and saltier the wateris, the greater its density).In the open oceans, currents flowclockwise in the northern hemisphere,anticlockwise in the southern. This is theCoriolis effect, caused by the direction ofrotation of the planet. Ocean currents havea great influence on climate. The warmGulf Stream, for example, brings relativelymild winters to northwestern Europe.

Only about 20% of Earth’s species live inthe oceans, of which about 90% arebottom-living, shallow-water species. Inmost ocean waters, especially the zonebelow a depth of 1000 metres where nolight penetrates, life is extremely sparse.There are two main ocean habitats: thewater itself, or pelagic habitat, and theocean floor, called the benthic habitat. Bothhabitats are subdivided into several zones,according to the amount of sunlight that isable to reach down through the water. Mostlife is concentrated in the upper 200 metreswhere tiny plants and animals calledplankton congregate, providing a richsource of food. But some animals survive inthe dark, near-freezing waters more than4000 metres down.

Warmed by the Sun,surface waters flow in

currents from the tropicstowards the poles, while

cold currents move in to taketheir place.

ARCTIC OCEAN

ATLANTICOCEAN

PACIFIC OCEAN

INDIAN OCEAN

SOUTHERN OCEAN

Warm currentCold current

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(NATURAL WORLD)

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Sea birds (see illustration, opposite) glideover the ocean waves, looking out for fish.Some birds scoop up fish from the surfacewith their beaks or feet, while others, suchas the booby, dive right into the water tograb their prey. Below the surface, small fishare preyed upon by larger, fast-movingpredatory fish, such as tuna or sharks. Theyalso fall prey to sea turtles, and mammalssuch as seals, dolphins and whales. With somany different predators, many fish haveevolved patterns of colour for camouflage,

or spiny or armoured skin, for protection.The surface waters are home to some ofthe largest animals in the world. Many ofthese, however, feed on the smallestcreatures of all, zooplankton. Baleen whales,such as the blue whale or the sei whale, aswell as some sharks like the basking shark,take in great mouthfuls of water and filterout vast quantities of a shrimp-likezooplankton called krill.

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SURFACE WATERS

THE RICHEST VARIETY of life inthe oceans is found in the surface

waters. Here, light from the sun penetratesthe water, allowing plants to grow. Unlikeland plants, oceanic plants cannot put downroots into the ground. Instead, they driftthrough the water in the form of tiny,usually single-celled organisms, known asphytoplankton. They use sunlight andnutrients dissolved in the water to makefood by the process of photosynthesis. Phytoplankton comprise most of theplant material found in the oceans (a smallamount also comes from seaweeds andshallow-water marine grasses). Able to growvery quickly, they are the first and vitalstage in the food web of the oceans. Phytoplankton are fed upon by tinyanimals called zooplankton. These includethe larvae (young) of fish, as well as tinyrelatives of crabs and shrimps, known ascopepods. They rise and fall through thewater, using the surface currents to carrythem along to new grazing areas. Planktonis richest in those parts of the ocean wherenutrients are stirred up from the ocean floor

by currents orwinds, such as KEY

1 Wanderingalbatross

2 Brown booby

3 Portugueseman-of-war

4 Flying fish

KEY1 Anchovies2 Tarpon3 Blue marlin4 Squid5 Hawksbill turtle6 Manta ray7 Skipjack tuna8 Sei whale9 Dolphinfish

The surface waters containthe most abundant foodsupply in the oceans.

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Phytoplankton (aboveleft), and the larger zoo -plankton (above right) thatfeed on them.

on the continental shelf (see page 4). In someoceans, the amount of plankton in thewater peaks in the spring and autumn.Many plankton-eating animals breed ormigrate to coincide with these peaks.Zooplankton provide food for a widerange of ocean animals. In an attempt toescape attention, many zooplankton haveconfusing colour patterns, and some areeven transparent. Fish and squid are majorpredators of zooplankton, and shoals ofsmall fish throng the surface waters. They inturn attract larger predators.The Portugueseman-of-war floats on the surface, trailing itsstinging tentacles down to catch small fish.



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Predators must adapt to an even greaterextent in an environment where prey isscarce, and where there may be long periodsof time between each successful attack. Fishsuch as the viperfish have long jaws andextremely long, needle-sharp teeth, whichare backward-pointing for stabbing andholding on to their prey. To take advantageof any prey animal they encounter, manypredators, such as the gulper eel, have hugejaws and stomachs that can stretch to holdfish even larger than themselves. Despite the blackness of the water, thereis still some light in the depths of the ocean.Some deepwater animals are able toproduce light from their own bodies, eitherfrom their tissues or from special light-producing organs. This feature is known asbioluminescence. These lights may act as alure to prey animals, or as a signal to othersof the same species in the search for mates.

They may also be “flashed” on andoff to confuse an attacker.

As well as the small predators that live inthe deep, larger animals also visit deepwaters to hunt for prey. Deep-living sharksand deep-diving whales feed on fish andsquid. Although whales need to come to thesurface to breathe, some are able to stayunderwater for long periods of time. Thesperm whale may dive to 3000 metresbelow the surface, and stay there for up totwo hours in search of its favourite prey,giant squid.

Many of the animals that live in the deepwaterzone look quite terrifying—apart from theirsmall size. The glowing “lamp” hanging fromthe head of the anglerfish family attractssmaller fish which mistake it for prey, only tobe snapped up themselves. Some anglerfishhave teeth that lie flat and then spring backaround their prey when it is inside theirmouths. The gulper eel conserves energy bylying in wait and ambushing its prey.

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DEEPWATER LIFE

LIGHT CANNOT penetrate very farthrough water, so after a depth of about200 metres there is little light, and below1000 metres the water is completely blackand very cold. Phyto plankton cannotsurvive here, and the amount of animal lifeis greatly reduced. As there is no source ofplant material to feed on, any creaturesliving in the deep waters need to findalternative sources of food. Some scavenging deepwater animals feedon the dead plant and animal matter thatrains down through the water from thesurface waters above. Others, such as thehatchetfish, travel up towards the surface tofeed, then return to the depths. On the way,they must avoid falling victim to the manypredatory deepwater animals that patrol thedark waters.

Between 200 metresand 1000 metresdeep, there is anarea of water knownas the twilight zone.Hatchetfish,lanternfish, and thedeadly siphonophore,a kind of jellyfish,migrate up towardsthe surface to feed.Barracudinas prey onany fish they canfind, their stomachsexpanding to takelarge prey. Theviperfish has aglowing rod on itsback to attract preytowards its mouth.

The six-gilled sharkhas six gill openingsinstead of the normalfive. Preferring the coldwaters of the deep, itfeeds on fish and raysnear the ocean floor.

KEY1 Siphonophore2 Loosejaw3 Argentine

4 Viperfish5 Barracudinas

6 Lanternfish7 Hatchetfish

Animals that live in the deep waters allthe time need to be specially adapted tosurvive. They are mostly small, and theirbodies are frail and lacking in muscle mass.These factors reduce the amount of energy,and therefore food, needed to maintaintheir bodies. They have large, extremelysensitive eyes to see in the near-blackwaters. Many are coloured brown or blackfor camouflage, to conceal themselves frompredators. Some prawns are bright red, butthis colour is invisible at such depths.

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KEY1 Vampire squid2 Anglerfish3 Gulper eels4 Anglerfish5 Prawns

The 15-metre-long tentacles of agiant squid can inflict deepscratches on a spermwhale during adeep-seabattle.

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Only a few kinds of fish are found closeto the ocean floor. Among these is the rat-tail, which has a large head and a long bodywhich tapers into an even longer tail. Itmakes a loud drumming noise by vibratingmuscles attached to its swim bladder (theorgan that keeps it afloat). This may be away of signalling to others of its kind.The tripod fish, as its name suggests,holds itself off the ocean floor on a “tripod”made of its long, stilt-like fins and tail. Itsinks the tips of its fins into the soft surfaceof the ooze, to support its body. Anotherpair of fins is held up in the air to detectthe movements of passing prey, whereuponthe tripod fish pushes itself forward to feed.

The ocean floor is littered with human waste, including oldfishing nets, cans and bottles and wrecks of sunken ships.Found on all parts of the ocean floor, especially beneathmajor shipping lanes, is clinker, burnt coal dumped fromsteamships during the period between the 1850s and 1950s.

KEY1 Rat-tail2 Sea pen3 Prawn4 Sea cucumber5 Tripodfish6 Sea cucumber7 Venus flower baskets8 Sea spider9 Sea cucumber10 Sea pens11 Sea urchin

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OCEAN FLOOR

AT THE LEVEL of the ocean floor,about 4500 metres deep, the water is

completely black, and very cold. Animalsliving there cannot use sight to find theirfood—in fact, many are blind. Instead, theyhave highly-developed senses of touch, orare able to detect chemical changes in thewater that lead them to a food source. The floor of the oceans is covered with athick layer of ooze, made up of sand, mudand tiny particles of rock, as well as debrisfrom plant and animal life in the watersabove. Some animals feed on this debris byburrowing into the ooze or creeping acrossit. Their digestive systems are speciallyadapted to process a diet of animal remains,including skeletons and droppings.

With their bases rooted in the ooze andtheir tentacles waving in the water, sea pens,relatives of corals and sea anemones, lookalmost like plants. Sponges such as the Venusflower basket also bed themselves into theooze, filtering out debris from the water.Spiky-skinned sea urchins and theirrelatives, the sea cucumbers, have branchedtentacles, known as tube-feet, beneath theirbodies. Some of these help them to moveacross or burrow into the ooze, while othersgather food from the water or the oceanfloor, and pass it to the mouth. As well as the scavengers, predatoryanimals are also found on the ocean floor.Sea spiders pick their way across the floor,their very long legs keeping them out ofthe soft ooze. They feed on sponges andburrowing worms.

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Without sunlight to grow plants, lifearound the black smokers relies on bacteria,which convert the sulphur dissolved in thewater into food. This process is known aschemosynthesis. The bacteria provide foodfor some animals, which are then prey forpredators. Tube worms and giant clamsactually have bacteria inside their bodies tomake food for them, as they do not havemouthparts or guts to feed themselves.

No-one knew of the existence of hydro -thermal vents until 1977, when they werediscovered by a team of scientists workingin a submersible near the GalapagosIslands in the Pacific Ocean.

KEY1 Black smoker2 Giant tube worms3 Lobster4 Giant clams

5 Eelpout6 Brotulid7 Crab

A small creature lookinga little like a dandelion isalso found near the blacksmokers. A kind ofsiphonophore (see page8), related to the jellyfish,this animal holds itselfabove the sea bed withfine tentacles. Othertentacles, armed withstinging cells, capture itsprey.

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BLACK SMOKERS

SNAKING ACROSS the ocean floor areundersea mountain chains known asmid-oceanic ridges. Here, the Earth’s crustis gradually spreading apart and magma, hotmolten rock from beneath the crust, rises tothe surface of the sea bed. In some placesalong a mid-oceanic ridge, water seepingdown into the rocks is heated by themagma. It shoots up through cracks in theocean floor, known as hydrothermal vents.

These jets of water are rich in mineralsfrom the Earth’s crust, especially sulphur. Asthe minerals emerge, they are graduallydeposited around the vents, creating tallchimneys. The sulphur turns the watersaround the vents black, and gives thesechimneys their name: “black smokers”.Most of the deep-sea ocean floor is verycold, with little animal life to be found. Thetemperature of the water shooting out ofthe black smokers, however, can be higherthan 300˚C. In the warm, mineral-richwater close by, an amazing amount of lifeflourishes. Some creatures are foundnowhere else in the world, and several kindsreach enormous sizes.

As magma rises, it spreads apart the oldrocks of the ocean floor. It then solidifies,forming a new part of the ocean floor.

Among the most peculiar animals aretube worms. These three-metre-long wormscluster together in intertwined masses, mostof their red bodies hidden inside white tubeshells. Giant clams also thrive around theblack smokers, while white, eyeless crabsand lobsters scavenge for scraps of foodstirred up by the warm, swirling waters.Even a few kinds of fish live here, includingthe eelpout and members of a group oflong-bodied fishes called brotulids, whichprefer to live in dark places.

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Molten rockrises

Oceanfloor

Crust

Mid-oceanicridge



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Modern submersibles cantravel to the deepestparts of the oceans. Thescientists inside breatheair that is stored onboard, and can direct thesubmersible through thewater. Submersibles havestrong searchlights, asthe waters are pitchblack below about 1000metres. They havecameras for the scientiststo take photographs orvideo footage. Some ofthe most fascinating partsof the ocean, such ashydrothermal vents (seepage 12), werediscovered by scientistsin submersibles. Deep-sea creatures never seenbefore have also beenphotographed andidentified.

OCEAN EXPLORATION

IN ORDER to explore the vast areasbelow the surface of the oceans, humansneed to be able to travel to great depthswithout having to return to the surfaceevery few minutes to breathe. Nineteenth-century divers wore heavy suits and dome-like helmets, with pipes leading up to thesurface through which air was pumped. Theinvention of the scuba diving system, whereair was carried in a tank on the diver’s back,gave divers much more freedom.However, below about 50 metres, waterpressure makes the air in the tanks too

concentrated. Divers who want to godeeper into the oceans have to breathe adifferent mixture of gases. After diving indeep, high-pressure waters, they enter adiving bell to return to surface pressurebefore they move up through the water.This stops nitrogen bubbles building upinside their blood, giving them the “bends”. At greater depths, divers use underwatervehicles called submersibles, which havethick metal walls to withstand the pressureof the water. Robot vehicles controlledfrom the surface, with cameras and sample-gathering equipment, are also used.

Scuba divers usually do not dive belowabout 50 metres. Robots such as Jasoncan travel down thousands of metres. Ithas lights to pierce the gloom and a TVcamera to record its surroundings.

Jason robot

Scuba diver

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OCEAN TRENCHES

THE DEEPEST places on Earth, oceantrenches are formed when the huge

plates that make up the Earth’s surface pushtogether, forcing one to slide beneath theother. This creates great chasms in the oceanfloor that can plunge down to 10,000metres deep. At such depths, the waterpressure is crushing, and the movement ofthe ocean floor creates frequent underwaterearthquakes. Incredibly, there are someanimals that can survive even here.

KEY1 Brotulid2 Sea anemone3 Sea cucumber4 Polychaete worm

Sea cucumbers (see page 10) creep acrossthe ooze that gathers at the bottom of thetrench. Worms and sea anemones burrowinto the sand to avoid predators such asbrotulid fish, the world’s deepest-living fish.These animals are specially adapted to livein such a high-pressure environment. Theirbodies have no air spaces inside them, andthey would die if they were brought upinto shallower, lower-pressure waters.

In 1960, scientists descended 10,911metres into the Marianas Trench in thePacific Ocean, in the submersible Trieste.

Ocean trenches are so black, cold andhostile that scientists have named them

the “hadal zone” after Hades, theGreek god of the underworld.

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The 15-metre-long whale shark and thesix-metre-wide manta ray also feed onplankton, as well as on tiny fish. Unlike theblue whale, which filters plankton from thewater through the horny plates in itsmouth, these giants filter plankton throughtheir gill slits. The whale shark has manyteeth, but they are tiny and useless.

The giant squid is the longestinvertebrate (animal without abackbone). Including its ten long,sucker- and hook-covered arms, it canmeasure 20 metres in length. No livespecimen has even been seen.

Blue whale

Diver

ALL ANIMALS TO SCALE

Leatherback turtle

Pacific octopus

Great white shark

Manta ray

Giant squid

Whale shark

Elephant seal

Sperm whale

Other ocean giants are predators of largerfish and other animals. The leatherbackturtle, almost two metres in length, dives to900 metres or more in search of jellyfish toeat. The Pacific octopus lives on the oceanfloor. It grabs crabs and lobsters with itslong arms, which can span nine metres.Elephant seals feed on fish and squid. Themales can weigh over two tonnes, threetimes as much as the females. The 18-metre-long sperm whale hunts deep-livinggiant squid (see page 9). Its huge head takesup one third of its whole length, andcontains a waxy substance that helps it tosink and rise through the water. Some of the most fearsome hunters inthe oceans are the predatory sharks. Thegreat white shark is usually about sevenmetres long. It feeds on sea mammals suchas seals and, despite its reputation, may oftenonly attack humans by mistake.

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OCEAN GIANTS

SOME OF the largest animals in theworld live in the oceans. They can growso large because the water supports theirhuge bodies. On land, even air-breathingmammals such as whales would die,collapsed under their own weight. They canalso grow to enormous sizes because of theabundance of food in the oceans. The vastquantities of plant and animal plankton (seepages 6-7) supports all ocean life, either byproviding food for small animals that arethen eaten by larger ones, or by feeding thelarge animals directly.In fact, some of the largest whales andsharks in the oceans feed only on tinyzooplankton such as krill, which are onlyfive centimetres long. The 30-metre-long

blue whale eats four tonnes of krill everyday, but as krill reproduce very quickly, theyremain abundant. Blue whales and otherplankton-eaters migrate to the polar regionsduring the summer. They feed on the highdensities of plant and animal plankton thatbuild up due to the rise in temperature andlong hours of sunlight.

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In rock pools (above), algaegrowing on the rocks areeaten by limpets, snails andperiwinkles, which arethemselves prey for starfishand whelks. Seaweeds arealso a source of food, aswell as a cool, damp shelterwhen the tide goes out.Crabs such as the hermitcrab, which takes over theshell of a dead animal,scavenge on animal debris.Birds such as oystercatchersand gulls probe the poolsand shore for worms, fishand shelled animals.

Every day, sea levels riseand fall in the movement ofthe tides. Tides are causedby the pull of the Moon’sgravity on the Earth. As theEarth rotates, the oceanwaters on the side of theEarth closest to the Moon(and the opposite side) arepulled into a bulge, causinga high tide (right). The restof the Earth has a low tide.When the Sun and Moon arein line, the Sun’s gravityincreases the pull to giveextra-high and extra-lowtides (far right).

Whelks,snails andslugs move

about on onelarge foot. Theyare known asgastro pods.

Sun

Moon

Moon

Earth Earth

Sun

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SEASHORE

THE SEASHORE is the place wherethe land meets the sea. It can consist of

rocky cliffs, a sandy beach or mudflatsbordering a river mouth or estuary. Theanimals and plants that live there must beable to survive the tides that cover them insalt water at certain times of the day, andleave them exposed to the air at othertimes. They live at different levels on theseashore according to how well they cansurvive out of water. Many kinds of seaweed dry out easily, andare found low down on the shore wherethey are covered with water all the time.Other more hardy varieties live further up

KEY1 Common tern2 Black-headed gull3 Herring gull4 Oystercatcher5 Limpets6 Mussels7 Periwinkle8 Barnacles9 Shore crab10 Prawn

11 Bladder wrack(seaweed)

12 Sea lettuce13 Starfish14 Stickleback15 Hermit crab16 Blenny17 Sea anemone18 Whelk

the shore. They anchor themselves to rocksto stop themselves being pulled away athigh tide, and are covered with mucus tohold in moisture when the tide goes out.Animals that live on sandy or muddyshores burrow into the ground at low tide,to keep moist and cool. On rocky shores,mussels clamp their shells tightly together,while limpets attach themselves to wetrocks to stop themselves drying out. Thisalso prevents them from being pulled awayby powerful waves when the tide comesback in. On some shores, tidal pools formbetween rocks. These are rich in life,including animals such as starfish, seaanemones and small fish, which could nototherwise survive so far up the shore.

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The coral reef provides places to hide forpredators and prey. The moray eel shootsout of a hole to grab passing fish. Clown -fish hide among the stinging tentacles ofsea anemones. Other fish would bekilled, but they remain unharmed.

Some corals arebranched, othersmound-shaped.Some look likecolourful flowers.

As fish, starfish and seaurchins feed on algaegrowing on corals, theybreak off pieces of deadcoral. These form thesandy beaches oftenfound on coral reefs.

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CORAL REEFS

CORAL is found in tropical shallowwaters around volcanic islands or close

to rocky mainland coastlines. It is madefrom layers of the skeletons of tiny animalscalled polyps. Over many years, colonies ofpolyps can build up great banks of coral,

known as reefs. There are many differentkinds of corals, and their bright coloursmake a coral reef look like an underseagarden. Only the living surface of the coralis coloured—the layers of dead polypsunderneath are white. The living layer oftiny polyps feed on zooplankton (see page 6)that drifts by in the current. Coral reefs are crowded with animal life.Tiny plants called algae, which drift in thecurrent or live on the bodies of the coral,are food for zooplankton, as well as forlarger animals such as fish and sea urchins.The crown-of-thorns starfish and theparrotfish feed on the coral itself. Manykinds of brightly-coloured fish throng thereef. Some feed on plankton, shellfish andother small creatures. Others, including thelargest predators such as sharks, eels andbarracudas, hunt smaller fish.

KEY1 Nautilus2 Squid3 Trunkfish4 Surgeonfish5 Triggerfish6 Seahorse7 Moray eel8 Hatchetfish9 Starfish10 Angelfish11 Octopus12 Moorish idol

13 Angelfish14 Butterflyfish15 Starfish16 Porcupinefish17 Seahorse18 Wrasse19 Grouper20 Surgeonfish21 Sea anemones22 Coral hind23 Angelfish24 Butterflyfish

25 Sweetlips26 Trumpetfish27 Damselfish28 Butterflyfish29 Jellyfish30 Tube sponge31 Clownfish

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On the coastline of South-

east Asia, the rainforest

merges into mangrove

swam

pland. Wading birds

such as storks feed on

crabs and fish, while

smaller birds hunt for

insects and snails. The

proboscis monkey (so-

called because of the

male’s long, drooping nose,

or proboscis) clambers

through the trees. It w

illswim through flooded areas

of forest, but must beware

of hungry tigers, crocodiles

and giant snakes.

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MANGROVE FORESTS are found on

sheltered, tropical coastlines. They are

formed in places such as the mouths of

rivers, where flowing salt water lays down

mud and other deposits, resulting in

swampy land. The roots of mangrove trees

are flooded with salt water when the tide

comes in. To avoid drowning, mangrove

trees have shallow root systems, that branch

up above the water line. This allows them to

breathe and also acts as a support for the

rest of the tree. The tangled mass of roots

traps nutrient-rich mud which provides

food for many kinds of animals.

The trees and plants of a mangrove forest

are home to numerous insects, while many

kinds of fish swim through the shallow

water between the tangled roots. Crabs,

snails and other small creatures burrow into

or crawl across the mud. These animals

provide food for frogs and a wide variety of

birds. Several kinds of monkey clamber

between the trees, feeding on fruits and

leaves. They are constantly on the lookout

for large predators, such as snakes and

crocodiles, which slip through the water or

bask on the mudflats.

In the mud left between tides, a

fish called the mudskipper skips

along on its fins. It breathes using

water stored in a chamber near its

gills, and can also take in oxygen

through its skin. At high tide, most

mudskippers retreat into their

burrows under the mud. Those left

above ground often climb trees to

avoid predatory fish.

Fiddler crabs scavenge in the mud at

the water’s edge. Their huge claws are

used to attract a mate or threaten a

rival. In the shallows, the archer fish

spits a jet of w

ater at insects or spiders

that are sitting on leaves above

the surface, m

aking them

fall into the water.

O C E A N S

22

KEY

1Ra

fflesia

2Tiger

3Re

ticulated python

4Proboscis monkey

5Ba

nded pitta

6Ga

vial

7Milky woodstork

8Mudskippers



150# DTP:95 PAGE:23



150# DTP:95 PAGE:25

Large predators are often absent fromislands, which means that some islandanimals do not need to be small and fast-moving. They can grow to larger sizes thantheir mainland relatives. It also means thatsome birds no longer need their escapemechanism of flight. Their wings becomesmall and useless, and they spend all theirtime on the ground. This adaptation makes

many flightless birds, such as the kakapo, aNew Zealand parrot, easy prey whenpredators are later introduced by humans.With a relatively small variety of animallife, competition between island species isreduced. One bird can eat a wide range offoods, which on the mainland would“belong” to several different birds. If moreanimals arrive, this lifestyle is threatened.

Giant tortoises (left) arefound in the GalapagosIslands and also in theSeychelles, in the IndianOcean. They have grownvery large due to a lackof predators. Some gianttortoises graze on lowgrasses, and have abroad shell that fits closeto the neck. Others havedomed shells with high,arched openings,allowing them to stretchtheir necks up to tallervegetation. Theintroduction by humans ofgrazing animals reducesthe tortoises’ food supplyand threatens theirsurvival.

Insects can grow tohuge sizes in islandhabitats. The giantweta, a kind ofcricket-like insectfrom New Zealand, isabout four times aslarge as an ordinarycricket. With nonatural predators, itis flightless, but isnow threatened byintroduced predatorssuch as rats.

The kiwi is aflightless bird fromthe forests of NewZealand. It lives inburrows, comingout at night to feedon worms.

O C E A N S

25

ISLAND LIFE

CUT OFF FROM the continental landmasses by stretches of ocean water,

islands often have a range of plant andanimal life that is uniquely their own. Someislands were once part of a larger land mass,while others are formed by underwatervolcanoes. As soon as an island forms, itbegins to be colonized by plants andanimals. Islands close to the main land arecolonized more quickly than remote ones.

Plant seeds can travel across the oceans.They rely on the wind or water to carrythem to islands. Seeds can also be carried inthe fur or feathers of animals, or even intheir digestive systems. The light seeds ofsmall plants can travel further on the windsthan those of large trees, so there aresometimes few, if any, trees on the mostremote islands. But these small plants may,over many years, evolve into larger ones.

The coconut palm is one ofthe few trees that candisperse their seeds overlong distances. The largecoconuts have a waterproofouter coating that allowsthem to float for thousands ofmiles to remote islands.

Many kinds of island-living birds nest inlarge colonies on remote cliffs, to avoidpredators that may steal their eggs. Puffins

dig burrows to nest in, or sometimestake over deserted rabbit burrows.They dive into the water to catchtiny sand eels.

Birds and swimming animals such as sealsare often the first animals to arrive on anew island. As well as carrying seeds on orinside their bodies, they carry insects andother tiny creatures. Insects are also blownto islands on the winds. As they increase inpopulation, they provide food for more andmore animals. Land animals sometimes find their way tonewly-formed islands on rafts of vegetationtorn from mainland coasts by savage storms.Others are brought to islands by humans.On remote islands, some animal species dieout, while others are able to adapt to theirnew surroundings, and build up a breedingpopulation. Over many years, new kinds ofanimals can evolve which are unique totheir island environment.

The blue-footed booby(left), nests on the steepcliff faces of the GalapagosIslands, off the coast ofSouth America. It plungesinto the water to feed onfish and squid. The maleand female take it in turnsto sit on their eggs.

The only lizards to feed inthe sea, marine iguanas(below) are also found inthe Galapagos Islands.They bask in the sun towarm up before diving intothe water to graze onseaweed and algae 15metres below the surface.

O C E A N S

24

•

1

3

2

1 2

3

5

4



150# DTP:95 PAGE:27

In winter, most of the ocean freezes overagain, and the days are short and dark.Without sunshine to make food, phyto -plankton cannot grow. Zooplankton sinkinto the depths of the ocean, where theyfeed on one another, or off fat reservesstored during the summer. Most of thelarger animals migrate south to find newsources of food. Polar bears are among thefew animals that remain. Some roam the iceor nearby land during the winter, whileothers dig dens in the snow to shelter fromthe harsh weather until the spring. Herefemales give birth to their cubs.

Many whales gather in theArctic Ocean during thesummer, but the narwhallives there all year round.Male narwhals have a long,spiralling tusk, which isactually one of their twoteeth. This may be used forfighting. Narwhals eat fish,squid, crabs and shrimp.

TUNDRA

THE LAND that borders the ArcticOcean is treeless, and the soil is

permanently frozen. For most of the year,this region, known as tundra, is a barrenwilderness, where plant and animal life isscarce. During the short summer, however,the ice in the top layer of the ground melts,and small plants can grow.Herds of caribou or reindeer (above, 1)arrive from the taiga forests to the south, tofeed on the new growth. The melted iceforms boggy patches where insects thrive,providing food for migrant birds. Smallmammals such as lemmings (2) that havespent the winter beneath the snow, arepreyed upon by Arctic foxes and owls (3).

O C E A N S

27

ARCTIC

MUCH OF THE Arctic Ocean iscovered with a thick layer of floating

ice all year round. At its edges, rafts ofbroken ice, called pack ice, drift in thefreezing cold waters. During the summer,some of the ice cracks and melts, formingwaterways and large stretches of water. No plants can grow on the Arctic ice, somost life is found in the waters around it.During the summer, the days becomelonger, and the sun warms the waters.Phyto plankton, tiny plant materialthat floats in the water, quicklygrows and multiplies in theseconditions, providing food formillions of tiny animals calledzooplankton (see page 6).

KEY1 Arctic tern2 Polar bear3 Bearded seal4 Narwhal5 Walrus

With the sudden increase in zooplankton,many animals migrate to the Arctic duringthe summer to exploit this rich source offood. Fish, squid, birds and even giantwhales feed on the zooplankton. A shrimp-like kind called krill is a particular favourite.Seals hunt the fish, while walruses search forshellfish and crabs on the sea bed with theirsensitive whiskers. The largest predators inthe waters are killer whales, which feed onfish and seals, while on the ice the hugepolar bear roams. Its white coat is perfectcamouflage while it waits to grab a seal as itemerges from a hole in the ice to breathe.

O C E A N S

26

NorthPole

ASIA

NORTHAMERICA

EUROPE

ARCTICOCEAN



150# DTP:95 PAGE:29

Antarctic animals are specially adapted tosurvive the cold, icy conditions and windsof up to 200 kilometres per hour. They havethick fur or feathers, and many also have alayer of fat, called blubber, to keep them

Antarctica is home to severalkinds of penguins. Theyspend most of their lives atsea, coming ashore to breedin large colonies on the ice.Emperor penguins are thelargest. After their eggs arelaid, the females return to thesea to feed. The males lookafter the eggs, carrying themon their feet to keep them offthe ice. In the coldestweather, they huddle togetherin circular groups. Six weekslater, the chicks hatch, themothers return and the fatherscan finally feed. Adélie penguins are the

favourite food of the leopardseal, which will also eatyoung seals, even of its ownkind. Adélie penguins are sofearful of this hunter that theyhesitate at the water’s edge,none daring to be first to takethe plunge.

warm. Some insects can survive beingfrozen during winter and defrosted insummer, while some kinds of fish have anatural “anti-freeze” in their blood to stopthem freezing in the icy waters.

O C E A N S

29

Just as in the Arctic, the main source offood for many animals is plankton. Phyto -plankton and zooplankton (see page 6) thrivein the Antarctic, due to nutrient-richcurrents and upwellings that swirl throughthe cold waters. Fish throng the waters,feeding on the zooplankton. Whales alsomigrate to the Antarctic to feed on vastquantities of krill. Despite its name, thecrabeater seal also feeds almost entirely onkrill—the only seal to do so.Other seals and penguins dive after fish,while sea birds such as albatrosses and ternspluck the fish from the surface. Penguinsand seals come out on to land to breed orrest, but when they return to the water,they are in danger from hunting killerwhales and the ferocious leopard seal.

In summer, humpback whales migratethousands of kilometres from their tropicalbreeding grounds to feed in the Antarctic.

O C E A N S

28

The ice cap extends acrossAntarctica. There are only afew small areas where theice melts enough for plantsto grow. No people livethere permanently,although explorers andscientists visit. At the edgeof the coastal ice shelf,colonies of penguins gather

(below), feeding on fish in thecold waters.

Australia

South PoleANTARCTICA

SOUTHAMERICA

AFRICA

ANTARCTICA

THE CONTINENT of Antarctica is ahuge, mountainous landmass, much of

it covered by a permanent icecap almostthree kilometres thick in some places. It isthe coldest place in the world. In winter,the waters of the Southern Oceansurrounding the continent are covered withfloating pack ice and icebergs that havebroken off the edges of the coastal ice shelf.Bitter winds sweep up snow from theground into fierce blizzards.The only places where plants can growon this barren land are along the coasts andaround the Antarctic Peninsula. Even then,they are mostly tiny mosses and lichensgrowing on the rocks. There is not enoughfood on the land to feed anything largerthan small insects, so the animals ofAntarctica are clustered around the coastsand islands, where the ocean waters providethem with plenty of food.

•

2

1

3

4

5



150# DTP:95 PAGE:31

Other rubbish dumped at sea includesfishing nets and ropes from ships or boats,and household waste such as cans, bottlesand plastic. This rubbish, some of whichtakes years to rot away, can entangle and killocean animals, especially birds andmammals. It also causes a hazard to peopleand animals when it washes up on beaches. Another major source of ocean pollutionis oil. Tankers carrying hundreds of tonnesof oil sometimes run aground, spilling theircontents into the water. The oil slick maybe carried ashore by the waves, pollutingthe coastline. Animals in the water and onthe shore become coated in the sticky oil,and many die. When the feathers of seabirds become clogged with oil, they losetheir warm, waterproof qualities. The birdsdrown, die of cold or are poisoned as theytry to preen away the oil with their beaks.

Ocean life is also threatened directly, byoverfishing, hunting and habitat destruction.Large-scale fishing operations, usingenormous nets that can catch many fish atonce, may cause some kinds of fish todecrease in number. This reduces theamount of food available for ocean animalsthat feed on these fish. At the same time,the nets may trap and kill animals such asdolphins and porpoises, turtles and sharks.

Manatees (right) livingalong the Florida coastare often injured by theincreasing numbers ofspeedboats to be foundin this popular touristresort.

Other ocean animals have been huntedby humans. Whales were hunted for theirmeat and oil, while sea otters and someseals were killed for their thick fur. Seaturtles have become increasingly rarebecause they are killed for their meat, andtheir eggs are stolen to be eaten as adelicacy. Many of the beaches where theylay their eggs have been taken over bydevelopment or tourism. The turtles, alongwith slow-moving mammals such asmanatees and whales, also suffer fromcollisions with boats. They can be injured oreven killed by high-speed boat propellers.

The vaquita (right) isa small porpoise,found only in the Gulfof California. A victimof fishing nets,there may onlybe a fewhundred lefttoday.

O C E A N S

31

ENDANGEREDOCEANS

THE EARTH’S OCEANS contain ahuge volume of water. Nevertheless,

they have been subjected to extensivepollution in recent years, endangering thelives of plants and animals, and quitepossibly storing up harmful consequencesfor the planet as a whole.Many of the waste products that pollutethe oceans come from the land. Modernchemicals that are sprayed on to crops tokill pests often do not decay naturally.Rainwater washes them into rivers, fromwhere they eventually flow down into theocean. Chemical fertilizers spread over fieldsalso flow from rivers into estuaries andcoastal waters. They encourage theunnatural growth of some kinds of algae,which reduce the amount of oxygen in thewater and kill off other life. Raw, untreatedsewage from our homes has the same effectwhen it is pumped out into the ocean, ortaken out to sea and dumped. It alsocontaminates shoreline sand or mud.

This illustration (below) shows some of theways in which the oceans can be polluted.Chemicals sprayed on to fields (1) run offinto rivers, and then into the sea. Somefactories discharge chemicals straight intothe sea (2), through large pipes. Otherstake it out to sea and dump it there,sometimes in large containers that fall onto the sea bed (3). A leaking oil tanker (4)can pollute whole stretches of coastline,while fishing boats (5) discard nets thatare hazardous to many kinds of wildlife.

Chemical waste from factories, includingpoisonous metals such as lead or mercury, isallowed to run into rivers or directly intothe ocean, or is dumped at sea. The harmfulchemicals collect on the sea bed, and aretaken in by bottom-living animals such asshellfish. The chemicals then pass into thebodies of the animals that feed on theshellfish. For the largest predators at the topof the food chain, including humans, theeffects can be deadly.

Grey whales used to live in theAtlantic Ocean, as well asthe Pacific. Theywere wiped out,probably bywhaling.

The Kemp’s ridley turtle breeds mainly onone beach in Mexico. Today, the numbersof turtles arriving to breed have fallen fromtens of thousands to only a few hundred.

O C E A N S

30

Sea otters suffer from the effects of oilpollution in the water in the same

way as sea birds. They rely onthe air trapped in their thickfur to keep them warm and

afloat. A coating of oilmakes them cold,wet and heavy.


150# DTP:95 PAGE:32

Aabyssal plain 4-5albatross, wandering 6algae 19, 20, 30anchovies 7angelfish 20-21anglerfish 9animals, endangered

30-31Antarctica 4, 28-29 Arctic life 26-27Arctic Ocean 4, 26-27Atlantic Ocean 4-5, 30

Bbarnacles 18-19barracudinas 8beaches 18, 30bear, polar 26-27bioluminescence 9black smokers 12-13bladder wrack (seaweed) 18-19

brotulid 12, 14burrows 24-25butterflyfish 20-21

Ccamouflage 6-7, 8, 26clam, giant 12clownfish 20-21coastlines 20, 22-23pollution of 30-31colonies 20, 29colonization 24competition 25continental shelf 4-5, 6coral 20, 10coral reefs 20-21Coriolis effect 4crabs 6, 12, 18-19, 22-23crocodile 22-23currents 4, 6

D Edamselfish 20-21deepwater life 8-9dolphinfish 7Earth 4-5, 12, 14, 19eel,gulper 9moray 20-21estuaries 18, 30evolution 24

N Onarwhal 26-27nautilus 20nutrients 6, 22, 28oceans 4-5, 6-21, 24-25, 26-27deepwater life 8-9, 10-15endangered 30-31exploration 15floor of the 4-5, 8, 10-

11, 12, 18giants of the 16-17surface waters 6-7, 8trenches 14octopus 20, 17organism 6otter, sea 31oystercatcher 18-19

PPacific Ocean 4-5, 13, 14, 30

penguin 29 periwinkle 18-19photosynthesis 6phytoplankton 6, 8, 26-27, 28,

plankton 4, 6-7, 8, 16-17,20, 26-27, 28

plants 4, 6, 8, 20, 26-27, 28

poles 4pollution 30-31polyps 20pools, tidal 18porcupinefish 20-21Portuguese man-of-war 6prawns 8-9, 11, 18-19puffin 24

Rrafflesia 22-23rainforest 22-23rat-tail 11ray, manta 7, 17reefs, coral 20-21reindeer 27ridge, mid-oceanic 5, 12rivers 22, 30robot vehicles 15rocks 5, 12, 18-19

Sscavengers 8, 10, 12, 19sea anemone 10, 14, 18-19, 20-21,

sea birds 7, 28, 31sea spider 10sea urchin 10, 20seahorse 20-21seals 7, 16-17, 26, 28, 24, 31

seashore 18-19

Ffilter-feeders 7, 10, 17fish 6-7, 8-9, 11, 12, 14, 17, 18, 20-21, 22-23,26-27, 28-29, 31

fishing 30-31floods 23food chain 30food web 6forest, mangrove 22-23taiga 27

G HGalapagos Islands 13, 24-25

gavial 23gills 8, 17grouper 20-21Gulf Stream 4gull 18-19habitats 4destruction of 30-31hatchetfish 8, 20hydrothermal vents

12-13, 15

Iice cap, Antarctic 28iguana, marine 24Indian Ocean 4, 25insects 22, 24-25, 27, 29flightless 25invertebrates 17island life 24-25

J K LJason robot 15jellyfish 8, 13, 20-21krill 7, 16, 26, 28lanternfish 8limpets 18-19lizards 24lobsters 12loosejaw 8

Mmagma 5, 12manatee 31mangroves 22-23Marianas Trench 14marlin, blue 7migration 6, 8, 16, 26-27,28

minerals 12Moorish idol 20moss 28mountains, undersea 12mudflats 18-19, 22mudskipper 23mussels 18

seaweed 6, 18-19seeds 24Seychelles 25sharks 7, 8-9, 16-17, 20, 31

siphonophore 8, 13slugs 19snails 19, 22 snakes 22-23soil 27Southern Ocean 4, 28sponges 10, 20-21squid 6-7, 9, 17, 20, 26starfish 18-19, 20-21submersibles 13, 14-15Sun 19surface waters 6-7, 8swamps 22-23

Ttaiga 27tarpon 7tern, Arctic 26common 18tides 4, 18-19, 22-23 tortoise, giant 25trees 24mangrove 22trench, deep-ocean 5, 14Trieste submersible 14triggerfish 20tropics 4, 22-23, 20trumpetfish 20-21trunkfish 20tuna, skipjack 7tundra 27turtles, sea 7, 16-17, 30-31

twilight zone 8

Vvaquita 31Venus flower basket 10viperfish 8-9

Wwalrus 26water,pollution of 30-31salt 18, 22weta, giant 25whales 7, 9, 16-17, 26-27, 28, 30-31

whaling 30-31whelk 18-19worms 10, 12, 14, 19

Zzooplankton 6-7, 16, 20, 26-27, 28

I N D E X

32

INDEXPage numbers in boldrefer to main entries.

children s illustrated encyclopedia ocean life...waters to hunt for prey. deep-living sharks and...

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